In general, a display using micro-light emitting diodes (micro-LEDs) is spotlighted as an advanced next generation display capable of replacing existing displays in the art. For manufacture of such a micro-LED display, a technique for transferring each LED to a modularized circuit board is needed.
In a typical method for transferring micro-LEDs to solders on a circuit board, the micro-LEDs are transferred one by one by a vacuum chuck. However, this method requires a very long time in manufacture of a display having a very large number of pixels, such as HD, UHD, SUHD, and the like. In addition, as the size of the devices decreases, this method has a problem of difficulty in handling devices such as micro-LEDs using the vacuum chuck used in an existing process.
Therefore, although there is a need for a technique for transferring a large number of micro-LEDs at the same time, such a technique has not been developed in the art and there is difficulty in the manufacturing process.
In order to solve such a problem, a roll transfer process can be used. However, this process has a problem in that roll transfer of micro-devices is very difficult to achieve due to very low adhesive strength of solder pastes when the micro-devices are transferred to a substrate using typical solder pastes.